In recent years, HDMI (High Definition Multimedia Interface) has been in widespread use as a communication interface that transmits a digital video signal, that is, an uncompressed (baseband) video signal (hereinafter referred to as “image data”) and a digital audio signal (hereinafter referred to as “audio data”) associated with the video signal from, for example, a DVD (Digital Versatile Disc) recorder, a set-top box, or another AV source (Audio Visual source) to a television receiver, a projector, or another display at high speed. For example, Patent Document 1 describes the HDMI specification in detail.
In addition, in recent years, in addition to widely used personal computers, even general consumer products have been frequently connected to the Internet. For terrestrial digital broadcasting and BS digital broadcasting, Ethernet is defined as means for providing EPG information. In general, television sets and apparatuses that support digital broadcasting have a RJ-45 connector mounted thereon.
Furthermore, as video recording means, video recording apparatuses that record video received via Ethernet are provided. Still furthermore, in the near feature, video distribution via the Internet, such as IP-TV, is planed to be provided. Therefore, in the near feature, apparatuses each having a plurality of Ethernet connectors may be commercially available. In such a case, loop connection may occur depending on how the terminals are connected.
For example, Patent Document 2 describes loop monitoring and detecting means that counts received MAC frames having the same FCS (Frame Check Sequence) value and determines that a network is in a loop mode if the number of received MAC frames having the same FCS value within a predetermined time period is a predetermined threshold value or greater.    Patent Document 1: Publication No. WO2002/078336    Patent Document 2: Japanese Unexamined Patent Application Publication No. 2006-13737